Contents of: VI/111/./abstract/DBEINTEM_PNEBULAE.abs

The following document lists the file abstract/DBEINTEM_PNEBULAE.abs from catalogue VI/111.
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SCIENTIFIC ABSTRACT

The objectives of this proposal are the following:

1. Investigate the abundances of iron, magnesium, silicon in planetary
nebulae. For iron, very little is known. For the other elements IUE
spectra are available, but only for some nearby nebulae. These elements
have useful lines in the SWS spectral range. We propose to measure these
abundances in a variety of nebulae.

2. Carbon abundances, as deduced from IUE observations, are not well
understood. To help resolve this question, we propose to try to observe
the CII line at 157 microns in a number of galactic-bulge nebulae, for
which we have reliable distance estimates. The NII line at 120 microns,
which will also be measured, will help in the interpretation, allowing to
distinguish between the central star and circumstellar material.

3. H2, OI and CII lines will be measured in a number of nebulae to try to
assess the amount of neutral material surrounding some nebulae. The OI
and CII lines are in the LWS range.

4. For two bright high-excitation nebulae full-resolution full SWS scans
will be made and a number of lines will be studied in more detail. The
results will serve as bench marks for other studies in the SWS Central
Program.

5. One extended nebula will be investigated by observing a number of
lines in a raster, to explore the excitation variations through the
nebula.


OBSERVATION SUMMARY

Observation modes are detailed in the scientific justification.


summary of proposed observations:


                            obs. modes            spring        autumn

 1 IC418                    S11 S2H P             34 min
 2 NGC 2346                 S11 S2  P             30 min
 3 NGC 2440                 S14     P            112 min
                                S2F               35 min
 4 NGC 3132                 S11 S2  P             30 min
 5 NGC 3242                 S11 S2  P             30 min
 6 NGC 3918                 S11 S2  P             30 min        30 min
 7 NGC 5315                 S11 S2  P                           30 min
 8 He2-113                  S11 S2H P                           34 min
 9 He 2-131                 S11 S2  P                           30 min
10 NGC 6153                 S11 S2  P                           30 min
11 NGC 6302                 S14     P                          112 min
                                S2F                             35 min
12 NGC 6543                 S11 S2  P             30 min        30 min
13 NGC 6537                 S11 S2  P                           30 min
14 NGC 6572                 S11 S2  P                           30 min
15 Vy 2-2                   S11 S2H P                           34 min
16 BD+30 3639               S11 S2H P                           34 min
17 IC4997                   S11 S2H P                           34 min
18 NGC 7027                 S14     P            112 min       112 min
                                S2F               35 min        35 min
19 IRAS21282+5050           S12     L             49 min        49 min
20 pk350+4.1                S12     L                           49 min
21 pk355+3.2                S12     L                           49 min
22 pk359-1.2                S12     L                           49 min
23 pk359-2.3                S12     L                           49 min
24 Cn 1-5                   S12     L                           49 min
25 NGC 246                  S2R                   12 min        12 min
26-36 NGC 246
   (continued, raster)      S2R                   99 min        99 min

Total                                            638 min      1045 min
                                                10.6 hrs      17.4 hrs



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